VFDs: Advice, Do's and Don'ts
Two schools of thought: buy one large enough to operate all your equipment, or buy one for each piece of your equipment. The best form of true three phase current without getting it directly from the power company. I think it is actually better. I converted my lathe from a 3 horsepower single phase motor to a 7 1/2 horse power 3 phase motor. Make sure you get a NEMA approved three phase motor, designed to be run with a VFD. Another piece of advise is if your lathe is metric get a metric motor.
For the best deals on VFDs and motors look up the Dealers Direct web site. They sell both new surplus VFDs and motors as well as used motors.
I bought a Westinghouse FM 215 in 2005, for my lathe. I think it was one of the best investments I have ever made in my shop. Be advised you may want an experienced electrician or engineer to wire it up. Mine has three wires going in and in the junction box there are 16 wires that have to be banked. Most VFDs will work on several different voltages.
Three phase will allow you to vary the frequency, have motor braking, and instant reverse. Due to the last you can rip the motor right off its bolts, and if your chuck is threaded send a spinning chuck loose in your shop. You can snap shear pins or break keyway keys or gear teeth. Wiring them correctly and using the features makes them much safer.
Nat Lambeth